The subject matter disclosed herein relates to a turbomachine and, more particularly, to a turbomachine with a transition piece having dilution holes and a fuel injection system coupled to the transition piece.
A typical turbomachine includes a combustor, a turbine and a transition piece. The combustor has a head end and includes a liner extending aft from the head end. The liner is formed to define a combustion zone in which a first quantity of fuel and compressed air are mixed and combusted to produce a main flow of products of combustion. The turbine is disposed downstream from the combustor and is configured to be receptive of the products of the combustion from the combustor. Within the turbine, the products of the combustion are expanded in power generation operations.
In some turbomachines that are configured for steam injection, steam is injected into the transition piece for power augmentation and cools down the flame. The turbomachine geometries are prescribed to set fuel/air ratios and, thus, flame temperatures, for emissions compliance during steam operation.
The drawbacks of steam injection system present themselves when the turbomachine 10 is run without steam injection (i.e., during dry operations). Emissions compliance in this case can only be maintained by under-firing the gas turbine and thereby producing less power output because of the turbomachine geometries being prescribed in accordance with steam operations. If the combustor geometry is prescribed to set fuel/air ratio and, thus, flame temperature, for emissions compliance during dry operation, then the drawbacks come when the turbomachine is run with steam. Emissions compliance in this case can be maintained only by over-firing the gas turbine, which leads to diminishing hot-gas-path parts' lives.